Exploring Prime and Composite Numbers - Free Printable

Let’s go step by step to fill in the table.

We need to find:
1. The list of factors for each number.
2. Whether the number is prime or composite.

Remember:
- A factor is a number that divides evenly into another number (no remainder).
- A prime number has exactly two factors: 1 and itself.
- A composite number has more than two factors.

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Let’s do each number one at a time:

Number: 10

Factors: 1, 2, 5, 10 → That’s 4 factors → Composite

Number: 5

Factors: 1, 5 → Only 2 factors → Prime

Number: 12

Factors: 1, 2, 3, 4, 6, 12 → 6 factors → Composite

Number: 18

Factors: 1, 2, 3, 6, 9, 18 → 6 factors → Composite

Number: 41

Check if any number besides 1 and 41 divides it.
Try dividing by 2? No — odd.
By 3? 4+1=5 → not divisible by 3.
By 5? Doesn’t end in 0 or 5.
By 7? 7×5=35, 7×6=42 → too big.
So only factors are 1 and 41 → Prime

Number: 15

Factors: 1, 3, 5, 15 → 4 factors → Composite

Number: 2

Factors: 1, 2 → Only 2 factors → Prime
*(Note: 2 is the smallest prime number!)*

Number: 49

Factors: 1, 7, 49 → Because 7×7=49 → So 3 factors → Composite

Number: 73

Check divisibility:
Not even → not divisible by 2.
Sum of digits: 7+3=10 → not divisible by 3.
Doesn’t end in 0 or 5 → not divisible by 5.
Try 7: 7×10=70, 73-70=3 → not divisible.
Try 11: 11×6=66, 11×7=77 → too big.
So only factors: 1 and 73 → Prime

Number: 33

Factors: 1, 3, 11, 33 → 4 factors → Composite

Number: 21

Factors: 1, 3, 7, 21 → 4 factors → Composite

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Now let’s put it all together in the table format as requested.

Final Answer:

| Number | List of Factors | Prime or composite? |
|--------|-------------------------|----------------------|
| 10 | 1, 2, 5, 10 | Composite |
| 5 | 1, 5 | Prime |
| 12 | 1, 2, 3, 4, 6, 12 | Composite |
| 18 | 1, 2, 3, 6, 9, 18 | Composite |
| 41 | 1, 41 | Prime |
| 15 | 1, 3, 5, 15 | Composite |
| 2 | 1, 2 | Prime |
| 49 | 1, 7, 49 | Composite |
| 73 | 1, 73 | Prime |
| 33 | 1, 3, 11, 33 | Composite |
| 21 | 1, 3, 7, 21 | Composite |